This section introduces aspects that may be helpful to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light. The statements of this section are not to be understood as admissions about what is in the prior art or what is not in the prior art.
Reconfigurable optical add/drop multiplexer network architectures often use arrays of tunable bandpass optical filters to add or drop a wavelength into or out of a network. The tunable bandpass optical filters should ideally have a box-like frequency response with fast roll-off skirt, should be physically small and should have low insertion loss.
Reconfigurable optical add/drop multiplexer network architectures also often require the use of a tunable bandpass optical filter for wavelength grooming. Free-space or MEMS based bandpass filters are widely used in such cases. Sometimes it can be difficult to make such filters tunable in bandwidth, and to integrate these filters with other network components.